myocardial infarction Flashcards
what part of actin myosin filament is sensitive to calcium concentration
troponin c
define myocardial infarction
specifically it is death of cardiac muscle due to lack of oxygen being supplied
what is used to diagnosed MI
troponin T and I which leak into blood when cardiac cell myocytes rupture during MI. T and I are unique to cardiac muscle
Why does an individual get chest pain upon MI, describe the pain
no somatic innervation of heart so a deep pain that can’t be localised, pain around neck chest and left arm,
metabolism is disrupted and adenosine is accumulating. a result of no oxygen
people with chest pain due to heart issue often confuse it with
indigestion
what is the advantage of coronary ateries being able to resist stenosis up until about 90 percent
resting blood flow through it can be maintained for a long time, enabling myocytes to be oxygenated
what is flow reserve
the ability for the conary ateries to dilate and increase blood flow when necessary due to increased demands
what is stable angina
flow reserve decreased due to stenosis, so when you exercise greater energy demand, not enough oxygen being delivered, adenosine buildup causing pain, if you rest demand goes down and flow reserve is enough. example of stable angina
name some of the characteristics of angina
Site and Radiation –Diffuse, Anterior chest, Left arm, Neck • Character –Tight, pressure, weight, constriction, dull • Triggers (angina) –Exercise, cold, meals, psychological stress • Relief (angina) –Rest, GTN • Duration –<30 mins angina –>30 mins infarction
why does someone expieriencing MI feel breathlessness and disorientated
occluded artery due to plaque rupture, no oxygen that part of the heart muscle dies or shuts down, or turns off what consumes the most energy e.g contraction, lack of oxygen to brain and other visceral organs causing increased breathing and brain not getting oxygen will cause disorientation
in right heart failure where is the oedma
ankle oedma
what does left heart failure result in
lung oeedma, thickening of liquid means co2 can still leave as it is soluble but harder for oxygen to enter, causing hypoxia
as heart failure increase what happens to frank starling mechanism
association between end diastolic pressure and cardiac output grows weaker and weaker
how does a thrombus from in coronary atery
rupture of atherosclerosis plaque, platelets adhesion to cholesterol and foam cells, starts clotting cascade traps blood in fibrogen web. blocks flow
what is used to treat people at risk of occluded arteries
aspirin anti platelet
what are the side effects of thrombolytic drugs
generalised lack of blood clotting risk of internal bleeding
what are the advantages of mechanical re-perfusion vs pharmacological treatment of coronary arteries
• Faster reperfusion • Higher % reperfusion • Less stroke and bleeds • Lower mortality
describe Balance between cardiac supply and
demand in healthy heart and abnormal one
in healthy heart supply and demand is always balanced, in an individual with CAD supply is reduced and demand is greater
what drugs improve supply demand balance
“Anti-anginals” –Beta-adrenoceptor blockers –L-type calcium channel blockers –Nitrates –ATP-sensitive potassium channel openers –If channel blockers
how do you stop a person who has had MI from suffering from it again, what areas do you target
• cholesterol • BP • ACE-I • Aspirin+ADP receptor antagonist • Betablockers • Statins Smoking Diabetes
distinguish between NSTEMI and STEMI
one has st elevtaion while the other has none, read up on the clinical implications for this and why it occurs
name three classes of drugs used to combat MI
chlesterol lowering, anti platelet, clot busters
state non modifiable risk for cardiovascular disease
Non-Modifiable
• Family history
• Age
• Sex
state modifiable cardiovascular disease risk
- Smoking
- High Cholesterol
- High Blood Pressure
- Diabetes
- Obesity/Diet/Exercise
- XS Alcohol
